Aye I have this too, the coloured pattern appears to depend on what was on the screen prior to this, the computer appears tocontinue to respond (as when I move the mouse around, I can see the bizarre stripey pattern change accordingly, and alt-tabbing to change windows changes a larger area of it etc, but nothing short of a shut down and restart will fix the problem. My problem started out a week after I recieved the laptop back from having a failed 6800 Go, but because it happens so intermittantly, I don't feel I could actually positively report my problem to dell and get any kind of useful feedback. (intermittant problems being as they are, intermittant, the problem would probably not manifest itself on dell's test bench, as it certainly doesn't cause any problems in the diagnostic problem)
fortuantely it only appears to happen at most once a day, and is caused by loading a 3d game. (doesn't get as far as showing one accelerated frame, instantly changes, if the problem is going to happen at all).
Any thoughts as to what I ought to do from a mod would be greatly appreciated.

Alex